This invention relates to a swash plate type compressor of the type often used for an air conditioning system of a car, especially to an improvement of a silencing means of such a swash plate type compressor.
A swash plate type compressor is provided with a plurality of cylinder bores and pistons sliding in the cylinder bores. Compressed gas is intermittently discharged from each of the cylinder bores into a high pressure chamber. The compressed gas generates pressure pulsations. The frequency of a fundamental wave of the pressure pulsation is in proportion to the rotational speed of the drive shaft of the compressor. In addition to the fundamental wave, higher harmonics are generated when the gas is discharged from the cylinder bores into the high pressure chamber through a discharge valve, because the gas flow is restricted by the discharge valve. The frequency of the higher harmonics is 400 to 1,000 Hz (cycles per second).
The pressure pulsations are transmitted to a condenser through a pipe. The higher harmonics of the pressure pulsations are one of the sources of vibration of a car body and a resonant sound in a car, in instances where such a compressor is used for a car air conditioning system.
In compressors of this general type, in order to reduce the vibration and resonant sound, it has been contemplated to provide silencing means outside the compressor. Such silencing means required additional space around the compressor, thereby making it difficult to effectively utilize the space in an engine room of a car.
Japanese Published Utility Model Application No. 50-44313, filed in 1975, discloses a silencing chamber. The silencing chamber is downstream of the high pressure chamber and is communicated therewith through a plurality of holes. The silencing chamber and the high pressure chamber are made in a body in a side cover. Accordingly the conventional side cover must be exchanged for a side cover provided with a silencing chamber therein. Further, since a structure of the side cover with a silencing chamber is complicated, the manufacturing precision for casting the side cover is low. It is also difficult to cast the side cover with a silencing chamber. Furthermore, with such a construction, the volume of the compressor as a whole is large.
An object of the present invention is to provide a swash plate type compressor provided with a silencing means. In preferred embodiments, the compressor is constructed to be insertable in the compressor side cover in its entirety without requiring the making of a specially designed side cover.
Another object of the present invention is to provide a swash plate type compressor provided with a silencing means which is small in size and is easy to make.
In preferred embodiments of the present invention a silencing means is formed in a high pressure chamber of the side cover by disposing at least one partition plate member in the high pressure chamber.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.